Data from: The extracellular and cytoplasmic domains of Syndecan cooperate postsynaptically to promote synapse growth at the Drosophila neuromuscular junction

The heparan sulfate proteoglycan (HSPG) Syndecan (Sdc) is a crucial regulator of synapse development and growth in both vertebrates and invertebrates. In Drosophila, Sdc binds via its extracellular heparan sulfate (HS) sidechains to the receptor protein tyrosine phosphatase LAR to promote the morphological growth of the neuromuscular junction (NMJ). To date, however, little else is known about the molecular mechanisms by which Sdc functions to promote synapse growth. Here we show that all detectable Sdc found at the NMJ is provided by the muscle, strongly suggesting a post-synaptic role for Sdc. We also show that both the cytoplasmic and extracellular domains of Sdc are required to promote synapse growth or to rescue Sdc loss of function. We report the results of a yeast two-hybrid screen using the cytoplasmic domains of Sdc as bait, and identify several novel candidate binding partners for the cytoplasmic domains of Sdc. Together, these studies provide new insight into the mechanism of Sdc function at the NMJ, and provide enticing future directions for further exploring how Sdc promotes synapse growth.24B Sdc RNAi Sdc and FasIIRaw image of muscle expressed Sdc RNAi, stained with Sdc and Fasciclin IIElav Sdc RNAi Sdc and FasIIRaw image of neural expressed Sdc RNAi, stained with Sdc and Fasciclin IISdc and FasII in wtRaw image of wild type 3rd instar larvum, stained with Sdc and Fasciclin II24BUASFLsdcmyc1Raw image of muscle expressed Sdc-FL, stained with HRP and anti-MycElav x UAS-Sdc mycRaw image of neural expressed Sdc-FL, stained with HRP and anti-MycCS for overexpressionRaw image of wild type larvum stained with HRP and anti-MycNormalized Bouton CountsRaw data and analyzed data on bouton counts used to generate bar graphs in Figure 224BUASFLsdcmyc1Raw image for Figure 324BUASsdcdeltaC1myc6Raw image for Figure 324BUASsdcdeltaC2myc8Raw image for Figure 324BUASsdcdeltaCytomyc14Raw image for Figure 3sdcdeltaectoRaw image for Figure 3sdctmswapRaw image for Figure 324bflsdcpbs3Raw image for Figure 424Bsdcdeltac1pbs13Raw image for Figure 424Bsdcdeltac2pbs11Raw image for Figure 424bsdcdeltacytopbs5Raw image for Figure 4sdcdeltaectoPBSRaw image for Figure 4sdctmswapPBSRaw image for Figure 4Normalized Bouton Counts ResubmissionThis file contains all the bouton counts for this manuscript